Functional fusing agent

ABSTRACT

Disclosed is a fusing release agent comprising the reaction product of a primary- or secondary-amino-functionalized polyorganosiloxane oil and a low molecular weight, non-sterically-hindered aldehyde or ketone.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a divisional of application Ser. No. 09/375,030, filed Aug. 16,1999 now U.S. Pat. No. 6,485,835.

BACKGROUND OF THE INVENTION

The present invention is directed to improved functional release agentsfor the fusing of electrostatic toner particles. More specifically, thepresent invention is directed to a functional polysiloxane fuser releaseagent with improved thermal stability. One embodiment of the presentinvention is directed to a composition comprising a mixture of (a) aprimary- or secondary-amino-functionalized polyorganosiloxane oil and(b) a compound which is a low molecular weight, non-sterically-hinderedaldehyde or ketone. Another embodiment of the present invention isdirected to a fusing release agent comprising the reaction product of(a) a primary- or secondary-amino-functionalized polyorganosiloxane oiland (b) a compound which is a low molecular weight,non-sterically-hindered aldehyde or ketone.

In a typical electrostatographic reproducing apparatus, a light image ofan original to be copied is recorded in the form of an electrostaticlatent image upon a photosensitive member, and the latent image issubsequently rendered visible by the application of electroscopicthermoplastic resin particles and pigment particles, or toner. Thevisible toner image is then in a loose powdered form and can be easilydisturbed or destroyed. The toner image is usually fixed or fused upon asupport, which can be the photosensitive member itself, or some othersupport sheet such as plain paper.

The use of thermal energy for fixing toner images onto a support memberis well known. To fuse electroscopic toner material onto a supportsurface permanently by heat, it is usually necessary to elevate thetemperature of the toner material to a point at which the constituentsof the toner material coalesce and become tacky. This heating causes thetoner to flow to some extent into the fibers or pores of the supportmember. Thereafter, as the toner material cools, solidification of thetoner material causes the toner to be bonded firmly to the support.

Typically, the thermoplastic resin particles are fused to the substrateby heating to a temperature of from about 90° C. to about 200° C. orhigher, depending on the softening range of the particular resin used inthe toner. It may be undesirable, however, to increase the temperatureof the substrate substantially higher than about 250° C. because of thetendency of the substrate to discolor or convert into fire at suchelevated temperatures, particularly when the substrate is paper.

Several approaches to thermal fusing of electroscopic toner images havebeen described. These methods include providing the application of heatand pressure substantially concurrently by various means, a roll pairmaintained in pressure contact, a belt member in pressure contact with aroll, a belt member in pressure contact with a heater, and the like.Heat can be applied by heating one or both of the rolls, plate members,or belt members. Fusing of the toner particles occurs when the propercombination of heat, pressure, and/or contact for the optimum timeperiod are provided. The balancing of these variables to bring about thefusing of the toner particles is well known in the art, and can beadjusted to suit particular machines or process conditions.

During the operation of one fusing system in which heat is applied tocause thermal fusing of the toner particles onto a support, both thetoner image and the support are passed through a nip formed between apair of rolls, plates, belts, or combination thereof. The concurrenttransfer of heat and the application of pressure in the nip effects thefusing of the toner image onto the support. It is important in thefusing process that minimal or no offset of the toner particles from thesupport to the fuser member takes place during normal operations. Tonerparticles offset onto the fuser member can subsequently transfer toother parts of the machine or onto the support in subsequent copyingcycles, thereby increasing the image background, causing inadequate copyquality, causing inferior marks on the copy, or otherwise interferingwith the material being copied there as well as causing tonercontamination of other parts of the machine. The referred to “hotoffset” occurs when the temperature of the toner is increased to a pointwhere the toner particles liquefy and a splitting of the molten tonertakes place during the fusing operation with a portion remaining on thefuser member. The hot offset temperature or degradation of the hotoffset temperature is a measure of the release properties of the fusermember, and accordingly it is desirable to provide a fusing surfacehaving a low surface energy to provide the necessary release.

To ensure and maintain good release properties of the fuser member, ithas become customary to apply release agents to the fuser member duringthe fusing operation. Typically, these materials are applied as thinfilms of, for example, silicone oils, such as polydimethyl siloxane, orsubstituted silicone oils, such as amino-substituted oils,mercapto-substituted oils, or the like, to prevent toner offset. Inaddition, fillers can be added to the outer layers of fuser members toincrease the bonding of the fuser oil to the surface of the fusermember, thereby imparting improved release properties.

The use of polymeric release agents having functional groups whichinteract with a fuser member to form a thermally stable, renewableself-cleaning layer having good release properties for electroscopicthermoplastic resin toners, is described in, for example, U.S. Pat. Nos.4,029,827, 4,101,686, and 4,185,140, the disclosures of each of whichare totally incorporated herein by reference. Disclosed in U.S. Pat. No.4,029,827 is the use of polyorganosiloxanes having mercaptofunctionality as release agents. U.S. Pat. Nos. 4,101,686 and 4,185,140are directed to polymeric release agents having functional groups suchas carboxy, hydroxy, epoxy, amino, isocyanate, thioether, and mercaptogroups as release fluids.

It is important to select the correct combination of fuser surfacematerial, any filler incorporated or contained therein, and fuser oil.Specifically, it is important that the outer layer of the fuser memberreact sufficiently with the selected fuser oil to obtain sufficientrelease. To improve the bonding of fuser oils with the outer surface ofthe fuser member, fillers have been incorporated into or added to theouter surface layer of the fuser members. The use of a filler can aid indecreasing the amount of fusing oil necessary by promoting sufficientbonding of the fuser oil to the outer surface layer of the fusingmember. It is important, however, that the filler not degrade thephysical properties of the outer layer of the fuser member, and it isalso important that the filler not cause too much of an increase in thesurface energy of the outer layer.

Fillers are also sometimes added to the outer layers of fuser members toincrease the thermal conductivity thereof. Examples of such fillersinclude conductive carbon, carbon black, graphite, aluminum oxide,titanium, and the like, as well as mixtures thereof. Efforts have beenmade to decrease the use of energy by providing a fuser member which hasexcellent thermal conductivity, thereby reducing the temperature neededto promote fusion of toner to paper. This increase in thermalconductivity also allows for increased speed of the fusing process byreducing the amount of time needed to heat the fuser member sufficientlyto promote fusing. Efforts have also been made to increase the toughnessof the fuser member layers to increase abrasion resistance and,accordingly, the life of the fuser member.

With regard to known fuser coatings, silicone rubber has been thepreferred outer layer for fuser members in electrostatographic machines.Silicone rubbers interact well with various types of fuser releaseagents. Perfluoroalkoxypolytetrafluoroethylene (PFA Teflon), however,which is frequently used as an outer coating for fuser members, is moredurable and abrasion resistant than silicone rubber coatings. Also, thesurface energy for PFA Teflon is lower than that of silicone rubbercoatings.

U.S. Pat. No. 5,864,740 (Heeks et al.), the disclosure of which istotally incorporated herein by reference, discloses a thermallystabilized silicone liquid composition and a toner fusing system usingthe thermally stabilized silicone liquid as a release agent, wherein thethermally stabilized silicone liquid contains a silicone liquid and athermal stabilizer composition (including a reaction product from atleast a polyorganosiloxane and a platinum metal compound (Group VIIIcompound) such as a ruthenium compound, excluding platinum.

U.S. Pat. No. 5,531,813 (Henry et al.), the disclosure of which istotally incorporated herein by reference, discloses a polyorgano aminofunctional oil release agent having at least 85 percent monoaminofunctionality per active molecule to interact with the thermally stableFKM hydrofluoroelastomer surface of a fuser member of anelectrostatographic apparatus to provide an interfacial barrier layer tothe toner and a low surface energy film to release the toner from thesurface.

U.S. Pat. No. 5,516,361 (Chow et al.), the disclosure of which istotally incorporated herein by reference, discloses a fusing system, amethod of fusing, and a fuser member having a thermally stable FKMhydrofluoroelastomer surface for fusing thermoplastic resin toners to asubstrate in an electrostatographic printing apparatus, said fusermember having a polyorgano T-type amino functional oil release agent.The oil has predominantly monoamino functionality per active molecule tointeract with the hydrofluoroelastomer surface to provide asubstantially uniform interfacial barrier layer to the toner and a lowsurface energy film to release the toner from the surface.

U.S. Pat. No. 5,512,409 (Henry et al.), the disclosure of which istotally incorporated herein by reference, discloses a method of fusingthermoplastic resin toner images to a substrate in a fuser including aheated thermally stable FKM hydrofluoroelastomer fusing surface atelevated temperature prepared in the absence of anchoring sites for arelease agent of heavy metals, heavy metal oxides, or other heavy metalcompounds forming a film of a fluid release agent on the elastomersurface of an amino functional oil having the formula

where 50≦n≦200, p is 1 to 5, R₁, R₂, and R₃ are alkyl or arylalkylradicals having 1 to 18 carbon atoms, R₄ is an alkyl or arylalkylradical having 1 to 18 carbon atoms and a polyorganosiloxane chainhaving 1 to 100 diorganosiloxy repeat units, and R₅ is a hydrogen,alkyl, or arylalkyl radical having 1 to 18 carbon atoms, the oil havingsufficient amino functionality per active molecule to interact with thehydrofluoroelastomer surface in the absence of a heavy metal and heavymetal anchoring sites to provide an interfacial barrier layer to thetoner and a low surface energy film to release the toner from thesurface. The process entails contacting the toner image on the substratewith the filmed heated elastomer surface to fuse the toner image to thesubstrate and permitting the toner to cool.

U.S. Pat. No. 5,493,376 (Heeks), the disclosure of which is totallyincorporated herein by reference, discloses a thermally stabilizedpolyorganosiloxane oil including a polyorganosiloxane oil and, as thethermal stabilizer, the reaction product of chloroplatinic acid and amember selected from the group consisting of a cyclic polyorganosiloxanehaving the formula

where R₃ is an alkyl radical having 1 to 6 carbon atoms and R₄ isselected from the group consisting of alkene and alkyne radicals having2 to 8 carbon atoms, and n is from 3 to 6; a linear polyorganosiloxanehaving the formula

wherein R₁ and R₂ are selected from the group consisting of hydroxy andalkyl, alkoxy, alkene, and alkyne radicals having 1 to 10 carbon atoms,provided that at least one of R₁ and R₂ is alkene or alkyne, and m isfrom 0 to 50; and mixtures thereof, present in an amount to provide atleast 5 parts per million of platinum in said oil.

U.S. Pat. No. 5,401,570 (Heeks et al.), the disclosure of which istotally incorporated herein by reference, discloses a fuser membercomprising a substrate and thereover a silicone rubber containing afiller component therein, wherein the filler component is reacted with asilicone hydride release oil.

U.S. Pat. No. 5,395,725 (Bluett et al.), the disclosure of which istotally incorporated herein by reference, discloses a process for fusingtoner images to a substrate which comprises providing a fusing memberhaving a fusing surface; heating the fuser member to an elevatedtemperature to fuse toner to the substrate; and applying directly to thefusing surface a fuser release agent oil blend composition; whereinvolatile emissions arising from the fuser release agent oil blend areminimized or eliminated.

U.S. Pat. No. 5,157,445 (Shoji et al.), the disclosure of which istotally incorporated herein by reference, discloses a fixing devicewhere a copying medium carrying a nonfixed toner image thereon is passedbetween a pair of fixing rolls as being kept in direct contact with eachother under pressure so as to fix the nonfixed toner image on thecopying medium, the device being characterized in that a toner releaseat least containing, as an active ingredient, a functional groupcontaining organopolysiloxane of the general formula

the organopolysiloxane having a viscosity of from 10 to 100,000 cs at25° C., is supplied to at least the fixing roll of being brought intocontact with the nonfixed toner image of the pair of fixing rolls. Usingthe toner release, the copying medium releasability from the fixing rollto which the toner release is applied is good and the heat resistance ofthe fixing roll is also good.

U.S. Pat. No. 4,515,884 (Field et al.), the disclosure of which istotally incorporated herein by reference, discloses the fusing of tonerimages to a substrate, such as paper, with a heated fusing member havinga silicone elastomer fusing surface by coating the elastomer fusingsurface with a toner release agent which includes an unblendedpolydimethyl siloxane having a kinematic viscosity of from about 7,000to about 20,000 centistokes. In a preferred embodiment the polydimethylsiloxane oil has a kinematic viscosity of from about 10,000 to about16,000 centistokes and the fuser member is a fuser roll having a thinlayer of a crosslinked product of a mixture of α,ω-dihydroxypolydimethylsiloxane, finely divided tabular alumina, and finely divided iron oxide.

U.S. Pat. No. 4,185,140 (Strella et al.), the disclosure of which istotally incorporated herein by reference, discloses polymeric releaseagents having functional groups such as carboxy, hydroxy, epoxy, amino,isocyanate, thioether, or mercapto groups which are applied to a heatedfuser member in an electrostatic reproducing apparatus to form thereon athermally stable, renewable, self-cleaning layer having excellent tonerrelease properties for conventional electroscopic thermoplastic resintoners. The functional polymeric fluids interact with the fuser memberin such a manner as to form a thin, thermally stable interfacial barrierat the surface of the fuser member while leaving an outer film or layerof unreacted release fluid. The interfacial barrier is strongly attachedto the fuser member surface and prevents electroscopic thermoplasticresin toner material from contacting the outer surface of the fusermember. The material on the surface of the fuser member is of minimalthickness and thereby represents a minimal thermal barrier.

U.S. Pat. No. 4,150,181 (Smith), the disclosure of which is totallyincorporated herein by reference, discloses a contact fuser assembly andmethod for preventing toner offset on a heated fuser member in anelectrostatic reproducing apparatus which includes a base member coatedwith a solid, abrasion resistant material such as polyimide,poly(amide-imides), poly(imide-esters), polysulfones, and aromaticpolyamides. The fuser member is coated with a thin layer of polysiloxanefluid containing low molecular weight fluorocarbon. Toner offset on theheated fuser member is prevented by applying the polysiloxane fluidcontaining fluorocarbon to the solid, abrasion resistant surface of thefuser member.

U.S. Pat. No. 4,146,659 (Swift et al.), the disclosure of which istotally incorporated herein by reference, discloses fuser members havingsurfaces of gold and the platinum group metals and alloys thereof forfuser assemblies in office copier machines. Preferred fuser assembliesinclude cylindrical rolls having at least an outer surface of gold, aplatinum group metal, or alloys thereof. Electroscopic thermoplasticresin toner images are fused to a substrate by using a bare gold, aplatinum group metal, or alloys thereof fuser member coated withpolymeric release agents having reactive functional groups, such as amercapto-functional polysiloxane release fluid.

U.S. Pat. No. 4,101,686 (Strella et al.), the disclosure of which istotally incorporated herein by reference, discloses polymeric releaseagents having functional groups such as carboxy, hydroxy, epoxy, amino,isocyanate, thioether, or mercapto groups. The release agents areapplied to a heated fuser member in an electrostatic reproducingapparatus to form thereon a thermally stable, renewable, self-cleaninglayer having excellent toner release properties for conventionalelectroscopic thermoplastic resin toners. The functional polymericfluids interact with the fuser member in such a manner as to form athin, thermally stable interfacial barrier at the surface of the fusermember while leaving an outer film or layer of unreacted release fluid.The interfacial barrier is strongly attached to the fuser member surfaceand prevents electroscopic thermoplastic resin toner material fromcontacting the outer surface of the fuser member. the material on thesurface of the fuser member is of minimal thickness and therebyrepresents a minimal thermal barrier.

U.S. Pat. No. 4,046,795 (Martin), the disclosure of which is totallyincorporated herein by reference, discloses a process for preparingthiofunctional polysiloxane polymers which comprises reacting adisiloxane and/or a hydroxy or hydrocarbonoxy containing silane orsiloxane with a cyclic trisiloxane in the presence of an acid catalystwherein at least one of the organosilicon compounds contain a thiolgroup. These thiofunctional polysiloxane polymers are useful as metalprotectants and as release agents, especially on metal substrates.

U.S. Pat. No. 4,029,827 (Imperial et al.), the disclosure of which istotally incorporated herein by reference, discloses polyorgano siloxaneshaving functional mercapto groups which are applied to a heated fusermember in an electrostatic reproducing apparatus to form thereon athermally stable, renewable, self-cleaning layer having superior tonerrelease properties for electroscopic thermoplastic resin toners. Thepolyorgano siloxane fluids having functional mercapto groups interactwith the fuser member in such a manner as to form an interfacial barrierat the surface of the fuser member while leaving an unreacted, lowsurface energy release fluid as an outer layer or film. The interfacialbarrier is strongly attached to the fuser member surface and preventstoner material from contacting the outer surface of the fuser member.the material on the surface of the fuser member is of minimal thicknessand thereby represents a minimal thermal barrier The polyorganosiloxanes having mercapto functionality have also been effectivelydemonstrated as excellent release agents for the reactive types oftoners having functional groups thereon.

U.S. Pat. No. 4,011,362 (Stewart), the disclosure of which is totallyincorporated herein by reference, discloses metal substrates such asmolds and fuser rolls which are coated with carboxyfunctional siloxanesto improve their release characteristics.

U.S. Pat. No. 3,731,358 (Artl), the disclosure of which is totallyincorporated herein by reference, discloses a silicone rubber roll forpressure fusing of electrostatically produced and toned images atelevated temperatures. The roll inherently prevents offset of the imageby supplying a release material to the surface of the roll. When therelease material is depleted, the roll can be restored by impregnationwith silicone oil.

U.S. Pat. No. 3,002,927 (Awe et al.), the disclosure of which is totallyincorporated herein by reference, discloses organosilicon fluids capableof withstanding high temperatures which are prepared by preoxygenatingthe fluid by heating a mixture of (1) a polysiloxane fluid in which thesiloxane units are selected from the group consisting of units of theformula R₃SiO_(0.5), R₂SiO, RSiO_(1.5), and SiO₂ in which each R isselected from the group consisting of methyl, phenyl, chlorophenyl,fluorophenyl, and bromophenyl radicals, (2) a ferric salt of acarboxylic acid having from 4 to 18 carbon atoms in an amount such thatthere is from 0.005 to 0.03 percent by weight iron based on the weightof (1), and (3) oxygen mechanically dispersed in the fluid at atemperature above 400° F. until the mixture changes to a reddish browncolor and until the mixture will not form a precipitate when heated inthe absence of oxygen at a temperature above that at which thepreoxygenation step is carried out.

With regard to known fusing oils, silicone oil has been the preferredrelease agent for PFA Teflon coatings for fuser members. Release agentscomprising silicone oil, however, do not provide sufficient releaseproperties for toner because the silicone oil does not wet fusercoatings of PFA Teflon. Therefore, a large amount (greater than 5mg/copy) of silicone oil is required to obtain minimum releaseperformance. Alternatively, a large amount of wax must be incorporatedinto the toner in order to provide adequate release of the toner fromthe fuser member.

For other fluoropolymer, and especially fluoroelastomer, fuser memberouter layers, amino silicone oil has been the release agent of choice.Amino oil, however, does not diffuse into paper products, but insteadreacts with the cellulose in the paper and therefore remains on thesurface of the paper. It is believed that hydrogen bonding occursbetween the amine groups in the amino oil and the cellulose hydroxygroups of the paper. Alternatively, the amine groups can hydrolyze thecellulose rings in the paper. The amino oil on the surface of the copiedpaper prevents the binding of glues and adhesives, including attachablenotes such as adhesive 3M Post-it® notes, to the surface of the copiedpaper. In addition, the amino silicone oil present on the surface of acopied paper prevents ink adhesion to the surface of the paper. Thisproblem results in the poor fix of inks such as bank check endorser inksand other similar inks.

Amino polyorganosiloxane oils also undergo degradation at a much fasterrate than nonfunctional polyorganosiloxane oils. Particularly when theoil is heated in the sump of the fusing apparatus, it is believed thatthe amino functional groups undergo thermal oxidative degradation andconvert to the reduced form after a period of time. Accordingly, afterthe oil has been heated in the sump for an extended period of time, theamine functionality of the oil (mole percent of amino groups in thepolymer) is reduced by the time it is introduced into the fusing nip.This difficulty cannot be overcome by raising the beginning aminefunctionality of the oil, because increasing the number of amino groupson the polymer by too great an amount can lead to gellation.

While known compositions and processes are suitable for their intendedpurposes, a need remains for improved fuser release agents. In addition,a need remains for amino-functional polyorganosiloxane fuser releaseagents with improved thermal stability. Further, a need remains foramino-functional polyorganosiloxane fuser release agents with improvedresistance to oxidative attack. Additionally, a need remains foramino-functional polyorganosiloxane fuser release agents that have thedesired degree of amino functionality when they enter the fusing nip,even after the fuser release agent has been heated for an extendedperiod of time. There is also a need for functional polyorganosiloxanefuser release agents that exhibit improved interactions with paper. Inaddition, there is a need for functional polyorganosiloxane fuserrelease agents that exhibit increased useful lifetimes. Further, thereis a need for functional polyorganosiloxane fuser release agents thatimprove the useful lifetimes of fuser members.

SUMMARY OF THE INVENTION

The present invention is directed to a composition comprising a mixtureof (a) a primary- or secondary-amino-functionalized polyorganosiloxaneoil and (b) a compound which is a low molecular weight,non-sterically-hindered aldehyde or ketone. Another embodiment of thepresent invention is directed to a fusing release agent comprising thereaction product of (a) a primary- or secondary-amino-functionalizedpolyorganosiloxane oil and (b) a compound which is a low molecularweight, non-sterically-hindered aldehyde or ketone.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an illustration of a general electrostatographic apparatus.

FIG. 2 illustrates a fusing system in accordance with an embodiment ofthe present invention.

FIG. 3 demonstrates a cross-sectional view of an embodiment of thepresent invention.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 1, in a typical electrostatographic reproducingapparatus, a light image of an original to be copied is recorded in theform of an electrostatic latent image on a photosensitive member, andthe latent image is subsequently rendered visible by the application ofelectroscopic thermoplastic resin particles, commonly referred to astoner. Specifically, photoreceptor 10 is charged on its surface by meansof a charger 12 to which a voltage has been supplied from power supply11. The photoreceptor is then imagewise exposed to light from an opticalsystem or an image input apparatus 13, such as a laser and lightemitting diode, to form an electrostatic latent image thereon.Generally, the electrostatic latent image is developed by bringing adeveloper mixture from developer station 14 into contact therewith.Development can be effected by use of a magnetic brush, powder cloud, orother known development process.

After the toner particles have been deposited on the photoconductivesurface in image configuration, they are transferred to a copy sheet 16by transfer means 15, which can be pressure transfer, electrostatictransfer, or the like. Alternatively, the developed image can betransferred to an intermediate transfer member and subsequentlytransferred to a copy sheet.

After transfer of the developed image is completed, copy sheet 16advances to fusing station 19, depicted in FIG. 1 as fusing and pressurerolls, wherein the developed image is fused to copy sheet 16 by passingcopy sheet 16 between fusing member 20 and pressure member 21, therebyforming a permanent image. Photoreceptor 10, subsequent to transfer,advances to cleaning station 17, wherein any toner left on photoreceptor10 is cleaned therefrom by use of a blade 22 (as shown in FIG. 1),brush, or other cleaning apparatus.

Referring to FIG. 2, an embodiment of a fusing station 19 is depictedwith an embodiment of a fuser roll 20 comprising polymer or elastomersurface 5 on a suitable base member or substrate 4, which in thisembodiment is a hollow cylinder or core fabricated from any suitablemetal, such as aluminum, anodized aluminum, steel, nickel, copper, orthe like, having a suitable heating element 6 disposed in the hollowportion thereof which is coextensive with the cylinder. The fuser member20 optionally can include an adhesive, cushion, or other suitable layer7 positioned between core 4 and outer layer 5. Backup or pressure roll21 cooperates with fuser roll 20 to form a nip or contact arc 1 throughwhich a copy paper or other substrate 16 passes such that toner images24 thereon contact polymer or elastomer surface 5 of fuser roll 20. Asshown in FIG. 2, an embodiment of a backup roll or pressure roll 21 isdepicted as having a rigid steel core 2 with a polymer or elastomersurface or layer 3 thereon. Sump 25 contains polymeric release agent 26,which may be a solid or liquid at room temperature, but is a fluid atoperating temperatures, and, in fuser members of the present invention,is the reaction product of (a) a primary- orsecondary-amino-functionalized polyorganosiloxane oil and (b) a compoundwhich is a low molecular weight, non-sterically-hindered aldehyde orketone. The pressure member 21 can also optionally include a heatingelement (not shown).

In the embodiment shown in FIG. 2 for applying the polymeric releaseagent 26 to polymer or elastomer surface 5, two release agent deliveryrolls 27 and 28 rotatably mounted in the direction indicated areprovided to transport release agent 26 to polymer or elastomer surface5. Delivery roll 27 is partly immersed in the sump 25 and transports onits surface release agent from the sump to the delivery roll 28. Byusing a metering blade 29, a layer of polymeric release fluid can beapplied initially to delivery roll 27 and subsequently to polymer orelastomer 5 in controlled thickness ranging from submicron thickness tothicknesses of several microns of release fluid. Thus, by meteringdevice 29, preferably from about 0.1 to about 2 microns or greaterthicknesses of release fluid can be applied to the surface of polymer orelastomer 5.

FIG. 3 depicts a cross-sectional view of another embodiment of theinvention, wherein fuser member 20 comprises substrate 4, optionalintermediate surface layer 7 comprising silicone rubber and optionalfillers 30, such as aluminum oxide or the like, dispersed or containedtherein, and outer polymer or elastomer surface layer 5. FIG. 3 alsodepicts a fluid release agent or fusing oil layer 9, which, in thepresent invention, comprises the reaction product of (a) a primary- orsecondary-amino-functionalized polyorganosiloxane oil and (b) a compoundwhich is a low molecular weight, non-sterically-hindered aldehyde orketone.

The term “fuser member” as used herein refers to fuser members includingfusing rolls, belts, films, sheets, and the like; donor members,including donor rolls, belts, films, sheets, and the like; and pressuremembers, including pressure rolls, belts, films, sheets, and the like;and other members useful in the fusing system of an electrostatographicor xerographic, including digital, machine. The fuser member of thepresent invention can be employed in a wide variety of machines, and isnot specifically limited in its application to the particular embodimentdepicted herein.

Any suitable substrate can be selected for the fuser member. The fusermember substrate can be a roll, belt, flat surface, sheet, film, orother suitable shape used in the fixing of thermoplastic toner images toa suitable copy substrate. It can take the form of a fuser member, apressure member, or a release agent donor member, preferably in the formof a cylindrical roll. Typically, the fuser member is made of a hollowcylindrical metal core, such as copper, aluminum, stainless steel, orcertain plastic materials chosen to maintain rigidity and structuralintegrity, as well as being capable of having a polymeric materialcoated thereon and adhered firmly thereto. It is preferred that thesupporting substrate is a cylindrical sleeve, preferably with an outerpolymeric layer of from about 1 to about 6 millimeters. In oneembodiment, the core, which can be an aluminum or steel cylinder, isdegreased with a solvent and cleaned with an abrasive cleaner prior tobeing primed with a primer, such as Dow Corning® 1200, which can besprayed, brushed, or dipped, followed by air drying under ambientconditions for thirty minutes and then baked at 150° C. for 30 minutes.

Also suitable are quartz and glass substrates. The use of quartz orglass cores in fuser members allows for a light weight, low cost fusersystem member to be produced. Moreover, the glass and quartz help allowfor quick warm-up, and are therefore energy efficient. In addition,because the core of the fuser member comprises glass or quartz, there isa real possibility that such fuser members can be recycled. Moreover,these cores allow for high thermal efficiency by providing superiorinsulation.

When the fuser member is a belt, the substrate can be of any desired orsuitable material, including plastics, such as Ultem®, available fromGeneral Electric, Ultrapek®, available from BASF, PPS (polyphenylenesulfide) sold under the tradenames Fortron®, available from HoechstCelanese, Ryton R-4®, available from Phillips Petroleum, and Supec®,available from General Electric; PAI (polyamide imide), sold under thetradename Torlon® 7130, available from Amoco; polyketone (PK), soldunder the tradename Kadel® E1230, available from Amoco; PI (polyimide);polyaramide; PEEK (polyether ether ketone), sold under the tradenamePEEK 450GL30, available from Victrex; polyphthalamide sold under thetradename Amodel®, available from Amoco; PES (polyethersulfone); PEI(polyetherimide); PAEK (polyaryletherketone); PBA (polyparabanic acid);silicone resin; and fluorinated resin, such as PTFE(polytetrafluoroethylene); PFA (perfluoroalkoxy); FEP (fluorinatedethylene propylene); liquid crystalline resin (Xydar®), available fromAmoco; and the like, as well as mixtures thereof. These plastics can befilled with glass or other minerals to enhance their mechanical strengthwithout changing their thermal properties. In preferred embodiments, theplastic comprises a high temperature plastic with superior mechanicalstrength, such as polyphenylene sulfide, polyamide imide, polyimide,polyketone, polyphthalamide, polyether ether ketone, polyethersulfone,and polyetherimide. Suitable materials also include silicone rubbers.Examples of belt-configuration fuser members are disclosed in, forexample, U.S. Pat. Nos. 5,487,707, 5,514,436, and Copending ApplicationU.S. Ser. No. 08/297,203, filed Aug. 29, 1994, the disclosures of eachof which are totally incorporated herein by reference. A method formanufacturing reinforced seamless belts is disclosed in, for example,U.S. Pat. No. 5,409,557, the disclosure of which is totally incorporatedherein by reference.

The optional intermediate layer can be of any suitable or desiredmaterial. For example, the optional intermediate layer can comprise asilicone rubber of a thickness sufficient to form a conformable layer.Suitable silicone rubbers include room temperature vulcanization (RTV)silicone rubbers, high temperature vulcanization (HTV) silicone rubbers,and low temperature vulcanization (LTV) silicone rubbers. These rubbersare known and are readily available commercially such as SILASTIC® 735black RTV and SILASTIC® 732 RTV, both available from Dow Corning, and106 RTV Silicone Rubber and 90 RTV Silicone Rubber, both available fromGeneral Electric. Other suitable silicone materials include the silanes,siloxanes (preferably polydimethylsiloxanes), such as fluorosilicones,dimethylsilicones, liquid silicone rubbers, such as vinyl crosslinkedheat curable rubbers or silanol room temperature crosslinked materials,and the like. Other materials suitable for the intermediate layerinclude polyimides and fluoroelastomers, including those set forthbelow.

Silicone rubber materials can swell during the fusing process,especially in the presence of a release agent. In the case of fusingcolor toner, normally a relatively larger amount of release agent isnecessary to enhance release because of the need for a larger amount ofcolor toner than is required for black and white copies and prints.Accordingly, the silicone rubber is more susceptible to swell in anapparatus using color toner. Aluminum oxide added in a relatively smallamount can reduce the swell and increase the transmissibility of heat.This increase in heat transmissibility is preferred in fusing membersuseful in fusing color toners, since a higher temperature (for example,from about 155 to about 180° C.) is usually needed to fuse color toner,compared to the temperature required for fusing black and white toner(for example, from about 50 to about 180° C.).

Accordingly, optionally dispersed or contained in the intermediatesilicone rubber layer is aluminum oxide in a relatively low amount offrom about 0.05 to about 5 percent by volume, preferably from about 0.1to about 5 percent by volume, and more preferably from about 2.2 toabout 2.5 percent by total volume of the intermediate layer. In additionto the aluminum oxide, other metal oxides and/or metal hydroxides can beused. Such metal oxides and/or metal hydroxides include tin oxide, zincoxide, calcium hydroxide, magnesium oxide, lead oxide, chromium oxide,copper oxide, and the like, as well as mixtures thereof. In a preferredembodiment, a metal oxide is present in an amount of from about 10 toabout 50 percent by volume, preferably from about 20 to about 40 percentby volume, and more preferably from about 30 to about 35 percent bytotal volume of the intermediate layer. In a preferred embodiment copperoxide is used in these amounts in addition to the aluminum oxide. In aparticularly preferred embodiment, copper oxide is present in an amountof from about 30 to about 35 percent by volume and aluminum oxide ispresent in an amount of from about 2.2 to about 2.5 percent by totalvolume of the intermediate layer. In preferred embodiments, the averageparticle diameter of the metal oxides such as aluminum oxide or copperoxide preferably is from about 1 to about 10 microns, and morepreferably from about 3 to about 5 microns, although the averageparticle diameter can be outside of these ranges.

The optional intermediate layer typically has a thickness of from about0.05 to about 10 millimeters, preferably from about 0.1 to about 5millimeters, and more preferably from about 1 to about 3 millimeters,although the thickness can be outside of these ranges. Morespecifically, if the intermediate layer is present on a pressure member,it typically has a thickness of from about 0.05 to about, 5 millimeters,preferably from about 0.1 to about 3 millimeters, and more preferablyfrom about 0.5 to about 1 millimeter, although the thickness can beoutside of these ranges. When present on a fuser member, theintermediate layer typically has a thickness of from about 1 to about 10millimeters, preferably from about 2 to about 5 millimeters, and morepreferably from about 2.5 to about 3 millimeters, although the thicknesscan be outside of these ranges. In a preferred embodiment, the thicknessof the intermediate layer of the fuser member is higher than that of thepressure member, so that the fuser member is more deformable than thepressure member.

Examples of suitable outer fusing layers of the fuser member includepolymers, such as fluoropolymers. Particularly useful fluoropolymercoatings for the present invention include TEFLON®-like materials suchas polytetrafluoroethylene (PTFE), fluorinated ethylenepropylenecopolymer (FEP), perfluorovinylalkylether tetrafluoroethylene copolymer(PFA TEFLON®), polyethersulfone, copolymers and terpolymers thereof, andthe like. Also suitable are elastomers such as fluoroelastomers.Specifically, suitable fluoroelastomers are those described in, forexample, U.S. Pat. Nos. 5,166,031, 5,281,506, 5,366,772, 5,370,931,4,257,699, 5,017,432, and 5,061,965, the disclosures of each of whichare totally incorporated herein by reference. These fluoroelastomers,particularly from the class of copolymers, terpolymers, andtetrapolymers of vinylidene fluoride, hexafluoropropylene, andtetrafluoroethylene and a possible cure site monomer, are knowncommercially under various designations as VITON A®, VITON E®, VITONE60C®, VITON E430®, VITON 910®, VITON GH®, VITON GF®, VITON E45®, VITONA201C®, and VITON B50®. The VITON® designation is a Trademark of E. I.Du Pont de Nemours, Inc. Other commercially available materials includeFLUOREL 2170®, FLUOREL 2174®, FLUOREL 2176®, FLUOREL 2177®, FLUOREL2123®, and FLUOREL LVS 76®, FLUOREL® being a Trademark of 3M Company.Additional commercially available materials include AFLASTM, apoly(propylene-tetrafluoroethylene), and FLUOREL II® (LII900), apoly(propylene-tetrafluoroethylenevinylidenefluoride) elastomer, bothalso available from 3M Company, as well as the TECNOFLONS® identified asFOR-60KIR®, FOR-LHF®, NM®, FOR-THF®, FOR-TFS®, TH®, and TN505®,available from Montedison Specialty Chemical Company. Fluoropolymer, andespecially fluoroelastomer, materials such as the VITON® materials, arebeneficial when used as fuser roll coatings at normal fusingtemperatures (e.g., from about 50 to about 150° C.). These materialshave the superior properties of high temperature stability, thermalconduction, wear resistance, and release oil swell resistance.

Particularly preferred polymers for the outer layer include TEFLON®-likematerials such as polytetrafluoroethylene (PTFE), fluorinatedethylenepropylene copolymers (FEP), and perfluorovinylalkylethertetrafluoroethylene copolymers (PFA TEFLON®), such aspolyfluoroalkoxypolytetrafluoroethylene, and are often preferred becauseof their increased strength and lower susceptibility to stripper fingerpenetration. Further, these preferred polymers, in embodiments, providethe ability to control microporosity, which further provides oil/filmcontrol. Other preferred outer surface layers include polymerscontaining ethylene propylene diene monomer (EPDM), such as those EPDMmaterials sold under the tradename NORDEL®, available from E. I. Du Pontde Nemours & Co., an example of which is NORDEL® 1440, and POLYSAR® EPDM345, available from Polysar. In addition, preferred outer surface layersinclude butadiene rubbers (BR), such as BUDENE® 1207, available fromGoodyear, butyl or halobutyl rubbers, such as, EXXON Butyl 365, POLYSARButyl 402, EXXON Chlorobutyl 1068, and POLYSAR Bromobutyl 2030. Polymerssuch as FKM materials (e.g., fluoroelastomers and silicone elastomers)are preferred for use in high temperature applications, and EPDM, BR,butyl, and halobutyl materials are preferred for use in low temperatureapplications, such as transfix and ink applications, and for use withbelts.

In another embodiment, the polymer is a fluoroelastomer having arelatively low quantity of vinylidene fluoride, such as in VITON GF®,available from E. I. DuPont de Nemours, Inc. The VITON GF® has 35percent by weight of vinylidene fluoride, 34 percent by weight ofhexafluoropropylene, and 29 percent by weight of tetrafluoroethylene,with 2 percent by weight cure site monomer. The cure site monomer can bethose available from Du Pont, such as4-bromoperfluorobutene-1,1,1-dihydro-4-bromoperfluorobutene-1,3-bromoperfluoropropene-1,1,1-dihydro-3-bromoperfluoropropene-1,or any other suitable cure site monomer. The fluorine content of theVITON GF® is about 70 percent by weight by total weight offluoroelastomer.

In yet another embodiment, the polymer is a fluoroelastomer havingrelatively low fluorine content such as VITON A201C, which is acopolymer of vinylidene fluoride and hexafluoropropylene, having about65 percent by weight fluorine content. This copolymer is compounded withcrosslinkers and phosphonium compounds used as accelerators.

Particularly preferred for the present invention are thefluoroelastomers containing vinylidene fluoride, such as the VITON®materials. Most preferred are the vinylidene fluoride terpolymers suchas VITON® GF.

It is preferred that the fluoroelastomer have a relatively high fluorinecontent of from about 65 to about 71 percent by weight, preferably fromabout 69 to about 70 percent by weight, and more preferably from about70 percent fluorine by weight of total fluoroelastomer. Less expensiveelastomers, such as some containing about 65 percent by weight fluorine,can also be used.

Other suitable fluoropolymers include those such as fluoroelastomercomposite materials, which are hybrid polymers comprising at least twodistinguishing polymer systems, blocks, or monomer segments, one monomersegment (hereinafter referred to as a “first monomer segment”) thatpossesses a high wear resistance and high toughness, and the othermonomer segment (hereinafter referred to as a “second monomer segment”)that possesses low surface energy. The composite materials describedherein are hybrid or copolymer compositions comprising substantiallyuniform, integral, interpenetrating networks of a first monomer segmentand a second monomer segment, and in some embodiments, optionally athird grafted segment, wherein both the structure and the composition ofthe segment networks are substantially uniform when viewed throughdifferent slices of the fuser member layer. The term “interpenetratingnetwork”, in embodiments, refers to the addition polymerization matrixwherein the polymer strands of the first monomer segment and the secondmonomer segment, as well as those of the optional third grafted segment,are intertwined in one another. A copolymer composition, in embodiments,comprises a first monomer segment and a second monomer segment, as wellas an optional third grafted segment, wherein the monomer segments arerandomly arranged into a long chain molecule. Examples of polymerssuitable for use as the first monomer segment or tough monomer segmentinclude, for example, polyamides, polyimides, polysulfones,fluoroelastomers, and the like, as well as mixtures thereof. Examples ofthe low surface energy monomer segment or second monomer segmentpolymers include polyorganosiloxanes and the like, and also includeintermediates that form inorganic networks. An intermediate is aprecursor to inorganic oxide networks present in polymers describedherein. This precursor goes through hydrolysis and condensation followedby the addition reactions to form desired network configurations of, forexample, networks of metal oxides such as titanium oxide, silicon oxide,zirconium oxide, and the like; networks of metal halides; and networksof metal hydroxides. Examples of intermediates include metal alkoxides,metal halides, metal hydroxides, and polyorganosiloxanes. The preferredintermediates are alkoxides, and particularly preferred are tetraethoxyorthosilicate for silicon oxide networks and titanium isobutoxide fortitanium oxide networks. In embodiments, a third low surface energymonomer segment is a grafted monomer segment and, in preferredembodiments, is a polyorganosiloxane. In these preferred embodiments, itis particularly preferred that the second monomer segment is anintermediate to a network of metal oxide. Preferred intermediatesinclude tetraethoxy orthosilicate for silicon oxide networks andtitanium isobutoxide for titanium oxide networks.

Also suitable are volume grafted elastomers. Volume grafted elastomersare a special form of hydrofluoroelastomer, and are substantiallyuniform integral interpenetrating networks of a hybrid composition of afluoroelastomer and a polyorganosiloxane, the volume graft having beenformed by dehydrofluorination of fluoroelastomer by a nucleophilicdehydrofluorinating agent, followed by addition polymerization by theaddition of an alkene or alkyne functionally terminatedpolyorganosiloxane and a polymerization initiator. Examples of specificvolume graft elastomers are disclosed in, for example, U.S. Pat. Nos.5,166,031, 5,281,506, 5,366,772, and 5,370,931, the disclosures of eachof which are totally incorporated herein by reference.

Examples of suitable polymer composites include volume graftedelastomers, titamers, grafted titamers, ceramers, grafted ceramers,polyamide-polyorganosiloxane copolymers, polyimide-polyorganosiloxanecopolymers, polyester-polyorganosiloxane copolymers,polysulfone-polyorganosiloxane copolymers, and the like. Titamers andgrafted titamers are disclosed in, for example, U.S. Pat. No. 5,486,987,the disclosure of which is totally incorporated herein by reference;ceramers and grafted ceramers are disclosed in, for example, U.S. Pat.No. 5,337,129, the disclosure of which is totally incorporated herein byreference; and volume grafted fluoroelastomers are disclosed in, forexample, U.S. Pat. No. 5,366,772, the disclosure of which is totallyincorporated herein by reference. In addition, these fluoroelastomercomposite materials are disclosed in U.S. Pat. No. 5,778,290, thedisclosure of which is totally incorporated herein by reference.

Other polymers suitable for use herein include silicone rubbers.Suitable silicone rubbers include room temperature vulcanization (RTV)silicone rubbers, high temperature vulcanization (HTV) silicone rubbers,and low temperature vulcanization (LTV) silicone rubbers. These rubbersare known and readily available commercially, such as SILASTIC® 735black RTV and SILASTIC® 732 RTV, both available from Dow Corning, and106 RTV Silicone Rubber and 90 RTV Silicone Rubber, both available fromGeneral Electric. Further examples of silicone materials include DowCorning SILASTIC® 590 and 591, Sylgard 182, and Dow Corning 806A Resin.Other preferred silicone materials include fluorosilicones, such asnonylfluorohexyl and fluorosiloxanes, including DC94003 and Q5-8601,both available from Dow Corning. Silicone conformable coatings, such asX3-6765, available from Dow Corning, are also suitable. Other suitablesilicone materials include the siloxanes (preferablypolydimethylsiloxanes), such as fluorosilicones, dimethylsilicones,liquid silicone rubbers (such as vinyl crosslinked heat curable rubbersor silanol room temperature crosslinked materials), and the like.Suitable silicone rubbers are available also from Wacker Silicones.

Conductive fillers can, optionally, be dispersed in the outer fusinglayer of the fuser member, particularly in embodiments wherein afunctional fuser oil is used. Preferred fillers are capable ofinteracting with the functional groups of the release agent to form athermally stable film which releases the thermoplastic resin toner andprevents the toner from contacting the filler surface material itself.This bonding enables a reduction in the amount of oil needed to promoterelease. Further, preferred fillers promote bonding with the oil withoutcausing problems such as scumming or gelling. In addition, it ispreferred that the fillers be substantially non-reactive with the outerpolymer material so that no adverse reaction occurs between the polymermaterial and the filler which would hinder curing or otherwisenegatively affect the strength properties of the outer surface material.Fillers in the outer fusing layer can also increase thermalconductivity.

Other adjuvants and fillers can be incorporated in the polymer of theouter fusing layer according to the present invention, provided thatthey do not affect the integrity of the polymer material. Such fillersnormally encountered in the compounding of elastomers include coloringagents, reinforcing fillers, processing aids, accelerators, and thelike. Oxides, such as magnesium oxide, and hydroxides, such as calciumhydroxide, are suitable for use in curing many fluoroelastomers. Protonacids, such as stearic acid, are suitable additives in EPDM and BRpolymer formulations to improve release by improving bonding of aminooils to the elastomer composition. Other metal oxides, such as cupricoxide and/or zinc oxide, can also be used to improve release. Metaloxides, such as copper oxide, aluminum oxide, magnesium oxide, tinoxide, titanium oxide, iron oxide, zinc oxide, manganese oxide,molybdenum oxide, and the like, carbon black, graphite, metal fibers andmetal powder particles such as silver, nickel, aluminum, and the like,as well as mixtures thereof, can promote thermal conductivity. Theaddition of silicone particles to a fluoropolymer outer fusing layer canincrease release of toner from the fuser member during and following thefusing process. Processability of a fluoropolymer outer fusing layer canbe increased by increasing absorption of silicone oils, in particular byadding fillers such as fumed silica or clays such asorgano-montmorillonites. Inorganic particulate fillers can increase theabrasion resistance of the polymeric outer fusing layer. Examples ofsuch fillers include metal-containing fillers, such as a metal, metalalloy, metal oxide, metal salt, or other metal compound; the generalclasses of suitable metals include those metals of Groups 1b, 2a, 2b,3a, 3b, 4a, 4b, 5a, 5b, 6b, 7b, 8, and the rare earth elements of thePeriodic Table. Specific examples of such fillers are oxides ofaluminum, copper, tin, zinc, lead, iron, platinum, gold, silver,antimony, bismuth, zinc, iridium, ruthenium, tungsten, manganese,cadmium, mercury, vanadium, chromium, magnesium, nickel, and alloysthereof. Also suitable are reinforcing calcined alumina andnon-reinforcing tabular alumina.

The polymer layers of the fuser member can be coated on the fuser membersubstrate by any desired or suitable means, including normal spraying,dipping, and tumble spraying techniques. A flow coating apparatus asdescribed in Copending Application U.S. Ser. No. 08/672,493 filed Jun.26, 1996, entitled “Flow Coating Process for Manufacture of PolymericPrinter Roll and Belt Components,” the disclosure of which is totallyincorporated herein by reference, can also be used to flow coat of aseries of fuser rolls. It is preferred that the polymers be diluted witha solvent, and particularly an environmentally friendly solvent, priorto application to the fuser substrate. Alternative methods, however, canbe used for coating layers, including methods described in CopendingApplication U.S. Ser. No. 09/069,476, filed Apr. 29, 1998, entitled“Method of Coating Fuser Members,” the disclosure of which is totallyincorporated herein by reference.

Other optional layers, such as adhesive layers or other suitable cushionlayers or conductive layers, can also be incorporated between the outerpolymer layer and the substrate. Optional intermediate adhesive layersand/or polymer layers can be applied to achieve desired properties andperformance objectives. An adhesive intermediate layer can be selectedfrom, for example, epoxy resins and polysiloxanes. Preferred adhesivesinclude materials such as THIXON 403/404, Union Carbide A-1100, DowTACTIX 740, Dow TACTIX 741, Dow TACTIX 742, Dow Corning P5200, DowCorning S-2260, Union Carbide A-1100, and United Chemical TechnologiesA0728. A particularly preferred curative for the aforementionedadhesives is Dow H41. Preferred adhesive(s) for silicone adhesion areA4040 silane, available from Dow Corning Corp., Midland, Mich. 48686,D.C. 1200, also available from Dow Corning, and S-11 silane, availablefrom Grace Specialty Polymers, Lexington, Mass. Adhesion of fluorocarbonelastomers can be accomplished with Chemlok® 5150, available from LordCorp., Coating and Lamination Division, Erie, Pa.

Polymeric fluid release agents can be used in combination with thepolymer outer layer to form a layer of fluid release agent, whichresults in an interfacial barrier at the surface of the fuser memberwhile leaving a non-reacted low surface energy release fluid as an outerrelease film.

The amino-substituted organosiloxane polymer in the present inventionhas primary or secondary amino functional groups pendant from at leastsome of the monomer repeat units of the polymer. Examples of preferredamino-substituted organosiloxane polymers include those of the generalformula

wherein R₁, R₂, R₃, R₄, R₅, R₆, R₇, R₈, and R₉ each, independently ofthe others, are alkyl or arylalkyl groups, including linear, branched,cyclic, unsaturated, and substituted alkyl and arylalkyl groups, thealkyl groups typically with from 1 to about 18 carbon atoms, preferablywith from 1 to about 8 carbon atoms, more preferably with from 1 toabout 6 carbon atoms, and even more preferably with from 1 to about 3carbon atoms, although the number of carbon atoms can be outside ofthese ranges, the arylalkyl groups (with either the alkyl or the arylportion of the group being attached to the silicon atom), includingsubstituted arylalkyl groups, typically with from 7 to about 18 carbonatoms, preferably with from 7 to about 12 carbon atoms, and morepreferably with from 7 to about 9 carbon atoms, although the number ofcarbon atoms can be outside of these ranges, wherein at least one of R₄,R₅, and R₉ can, if desired, also be a polyorganosiloxane chain with from1 to about 100 repeat diorganosiloxane monomer units (with the organicsubstituents being alkyl groups or arylalkyl groups as defined hereinfor R₁ through R₉), R₁₀ is an alkyl or arylalkyl group, includinglinear, branched, cyclic, unsaturated, and substituted alkyl andarylalkyl groups, the alkyl groups typically with from 1 to about 18carbon atoms, preferably with from 1 to about 8 carbon atoms, morepreferably with from 1 to about 6 carbon atoms, and even more preferablywith from 1 to about 3 carbon atoms, although the number of carbon atomscan be outside of these ranges, the arylalkyl groups (with either thealkyl or the aryl portion of the group being attached to the siliconatom) typically with from 7 to about 18 carbon atoms, preferably withfrom 7 to about 12 carbon atoms, and more preferably with from 7 toabout 9 carbon atoms, although the number of carbon atoms can be outsideof these ranges, with R₁₀ most preferably being an alkyl group with from1 to about 3 carbon atoms, such as an n-propyl group, R₁₁ is a hydrogenatom, an alkyl or arylalkyl group, including linear, branched, cyclic,unsaturated, and substituted alkyl and arylalkyl groups, the alkylgroups typically with from 1 to about 18 carbon atoms, preferably withfrom 1 to about 8 carbon atoms, more preferably with from 1 to about 6carbon atoms, and even more preferably with from 1 to about 3 carbonatoms, although the number of carbon atoms can be outside of theseranges, the arylalkyl groups (with either the alkyl or the aryl portionof the group being attached to the silicon atom) typically with from 7to about 18 carbon atoms, preferably with from 7 to about 12 carbonatoms, and more preferably with from 7 to about 9 carbon atoms, althoughthe number of carbon atoms can be outside of these ranges, and p and nare each integers representing the number of repeat monomer units;typically, p is from 1 to about 1,000 and n is from 0 to about 5,000,with the sum of p+n typically being from about 50 to about 5,000,although the number of repeat monomer units can be outside of thisrange. The value of p must be at least one in at least some of thepolyorganosiloxane molecules contained in the oil. These polymersgenerally are random copolymers of substituted and unsubstituted alkylor arylalkyl siloxane repeat units, although alternating, graft, andblock copolymers are also suitable. In one preferred embodiment, R₁, R₂,R₃, R₄, R₅, R₆, R₇, R₈, and R₉ are all methyl groups. Otherpolyorganosiloxanes, such as T-type functional polyorganosiloxanes, arealso suitable for the present invention.

The amino-substituted polyorganosiloxane is reacted with a low molecularweight, non-sterically-hindered aldehyde or ketone. Suitable aldehydesand ketones are of the general formula

wherein each of R₂₁ and R₂₂, independently of the other, is an alkylgroup (including linear, branched, saturated, unsaturated, cyclic,substituted, and unsubstituted alkyl groups), typically with from 1 toabout 5 carbon atoms, although the number of carbon atoms can be outsideof these ranges, wherein one of R₂₁ and R₂₂ can also be a hydrogen atom,wherein the substituents on the substituted alkyl, aryl, and arylalkylgroups can be (but are not limited to) hydroxy groups, amine groups,ammonium groups, cyano groups, pyridine groups, pyridinium groups, ethergroups, aldehyde groups, ketone groups, ester groups, amide groups,carbonyl groups, sulfide groups, sulfoxide groups, phosphine groups,phosphonium groups, nitrile groups, mercapto groups, nitroso groups,halogen atoms, nitro groups, sulfone groups, acyl groups, mixturesthereof, and the like, wherein two or more substituents can be joinedtogether to form a ring.

The amino-substituted polyorganosiloxane and the aldehyde are present inrelative amounts of at least about 25 moles of aldehyde or ketone permole of amino functional groups on the polyorganosiloxane, andpreferably in relative amounts of at least about 100 moles of aldehydeor ketone per mole of amino functional groups on the polyorganosiloxane,although the relative amounts can be outside of these ranges.

The reaction between the amino-substituted polyorganosiloxane and thealdehyde or ketone takes place when the aldehyde or ketone is dissolvedor dispersed in the amino-substituted polyorganosiloxane, followed byheating, typically at temperatures of from about 300 to about 550° F.,although the reaction temperature can be outside of this range. Thereaction between the amino-substituted polyorganosiloxane and thealdehyde or ketone generally occurs in the oil sump of the fusingapparatus as a normal function of the fusing process; the aldehyde orketone is dissolved or dispersed in the oil, and the additive-containingoil is added to the oil sump, which is heated during the fusing process.

While not being limited to any particular theory, it is believed thatthe reaction product of the amino-substituted polyorganosiloxane withthe aldehyde or ketone is a Schiff base, probably of the general formula

wherein R₁, R₂, R₃, R₄, R₅, R₆, R₇, R₈, R₉, R₁₀, R₂₁, and R₂₂ are asdefined hereinabove. Again, while not being limited to any particulartheory, it is believed that the reaction product of theamino-substituted polyorganosiloxane and the aldehyde or ketone isrelatively unreactive (compared to the amino-substitutedpolyorganosiloxane itself), and thus does not undergo thermal oxidativedegradation to the extent that would be observed with theamino-substituted polyorganosiloxane itself. Once exposed to atmosphericmoisture, however, it is believed that the Schiff base groups on thepolyorganosiloxane will revert to amino groups, and that the reactionconverting the oil back to the amino-substituted oil, in combinationwith the rapid cooling of the paper, both reduces the susceptibility ofthe oil to thermal oxidative degradation and reduces unwanted reactionsbetween the amino-substituted polyorganosiloxane and the paper surface.

Functional siloxane oils according to the present invention have anydesired or effective degree of substitution with functional groups. Ingeneral, the degree of substitution is such that the siloxane oil caninteract with the outer surface layer of the fuser member to form athermally stable, renewable self-cleaning layer thereon having goodrelease properties for electroscopic thermoplastic resin toners.Typically, there are from about 0.5 to about 10 functional groups perfunctional siloxane polymer molecule, preferably from about 1 to about 5functional groups per functional siloxane polymer molecule, and evenmore preferably 1 functional group per functional siloxane polymermolecule, although the degree of functionality can be outside of theseranges. Expressed in terms of mole percent functionality (which isparticularly useful when dealing with blends of functional andnonfunctional siloxane oils), the fusing agent is from about 0.01 molepercent to about 10 mole percent functionalized, and preferably fromabout 0.2 mole percent to about 2 mole percent functionalized, althoughthe degree of functionalization can be outside of these ranges. When thefunctional polyorganosiloxane is of the formula

wherein R₁, R₂, R₃, R₄, R₅, R₆, R₇, R₈, R₉, R₁₀, and R₁₁ are each asdefined hereinabove, preferably p is a number of from about 1 to about5, and more preferably is exactly 1, in at least about 50 percent of thesiloxane oil molecules, and more preferably in at least about 80 percentof the siloxane oil molecules, with the functional group substitutedmonomer repeat units being randomly situated in the polymer chains. Thevalue of $\frac{p}{n + p}$

typically is from about 0.0001 to about 0.1, and preferably is fromabout 0.002 to about 0.02. This number represents the amount offunctional groups present in the concentrate relative to the number oforganosiloxane (—SiR₂—) groups present in the concentrate. It will beappreciated that some individual polymer molecules in the concentratemay have no functional substituents thereon, and that some individualpolymer molecules in the concentrate may have 2, 3, 4, 5, or morefunctional substituents thereon.

The organosiloxane polymer release agents are of any suitable or desiredeffective weight average molecular weight, typically from about 3,600 toabout 80,000, and preferably from about 6,000 to about 70,000, and morepreferably from about 10,000 to about 30,000, although the weightaverage molecular weight can be outside of these ranges. Typical numberaverage molecular weights are from about 5,000 to about 20,000, althoughthe number average molecular weight can be outside of this range.

The polyorganosiloxane oils of the present invention have any desired oreffective viscosity, typically from about 100 to about 15,000centistokes, preferably from about 100 to about 1,000 centistokes, andmore preferably from about 100 to about 350 centistokes at about 25° C.,although the viscosity can be outside of these ranges.

The polyorganosiloxane oils of the present invention remain functionallyfluid at temperatures typically of up to about 500° F., and preferablyfrom about 30 to about 450° F., although the temperatures at which therelease agents are functionally fluid can be outside of these ranges.

Preferably, the release agent forms a continuous film on the polymersurface of the fuser member. The silicone oils of the present inventiontypically are supplied in an amount of from about 0.1 to about 20microliters per copy, preferably from about 2 to about 15 microlitersper copy, and more preferably from about 3 to about 5 microliters percopy, although the amount can be outside of these ranges.

The present invention is also directed to a process which comprises (a)generating an electrostatic latent image on an imaging member; (b)developing the latent image by contacting the imaging member with adeveloper; (c) transferring the developed image to a copy substrate; and(d) affixing the developed image to the copy substrate by contacting thedeveloped image with a fuser member comprising a substrate, a layerthereover comprising a fluoropolymer, and, on the fluoropolymeric layer,a coating of a release agent according to the present invention.Examples of suitable substrates include (but are not limited to) plainpapers such as Xerox ® 4024 papers, ruled notebook paper, bond paper,silica coated papers such as Sharp Company silica coated paper, Jujopaper, and the like, transparency materials, fabrics, textile products,plastics, polymeric films, inorganic substrates such as metals and wood,and the like. The present invention also encompasses an image formingapparatus for forming images on a recording medium which comprises: a) acharge-retentive surface capable of receiving an electrostatic latentimage thereon; b) a development assembly to apply toner to thecharge-retentive surface, thereby developing the electrostatic latentimage to form a developed image on the charge retentive surface; c) atransfer assembly to transfer the developed image from the chargeretentive surface to a copy substrate; and d) a fixing assembly to fusetoner images to a surface of the copy substrate, wherein the fixingassembly includes a fuser member comprising a substrate, a layerthereover comprising a fluoropolymer, and, on the fluoropolymeric layer,a coating of a release agent according to the present invention.

Specific embodiments of the invention will now be described in detail.These examples are intended to be illustrative, and the invention is notlimited to the materials, conditions, or process parameters set forth inthese embodiments. All parts and percentages are by weight unlessotherwise indicated.

EXAMPLE I

An amino-functional polyorganosiloxane fusing oil (350 centiStokes, 0.06mole percent amino functionality, D.C. 2-8783, obtained from DowCorning, Midland, Mich.) was combined with methyl ethyl ketone toproduce a 100:1 Molar ratio of methyl ethyl ketone to amine functionalgroups and mixed overnight by roll mill. For comparison purposes,additional mixtures were prepared by the same process, one consisting ofthe D.C. 2-8783 fuser oil and acetophenone (100:1 Molar ratio ofacetophenone to amine functional groups), and another consisting of theD.C. 2-8783 fuser oil and benzophenone (100:1 Molar ratio ofacetophenone to amine functional groups). The resulting mixtures wereadded to the oil sumps of fusing test fixtures. A control fusing oil,consisting solely of the D.C. 2-8783 fuser oil but containing noaldehyde or ketone, was also added to the oil sump of a fusing testfixture. The oils were heated to a temperature of 375° F. in the testfixture oil sumps. When the fusing oils were fixture tested, the life ofthe amine functionality in the oil containing the methyl ethyl ketoneadditive was increased by 25 percent (in copy count) compared to thecontrol oil containing no aldehyde or ketone. The time of decay of aminefunctionality was also reduced. Under identical conditions:

Fusing Oil Fuser Role Life (copies) DC 2-8783 83,000 DC 2-8783 + methylethyl ketone 103,000 DC 2-8783 + acetophenone 83,000

As the data indicate, the methyl ethyl ketone reacted with theamino-functional oil to produce the reaction product of the presentinvention, thereby increasing the fuser roll life. In contrast, theacetophenone, a relatively sterically hindered ketone, did not undergoany reaction with the amino-functional oil, and did not increase thefuser role life. Additional laboratory testing performed by NMR studiesof the reaction mixture before and after any possible reaction indicatedthat methyl ethyl ketone underwent a reaction with the amino-functionaloil, but that acetophenone and benzophenone underwent no reaction withthe amino-functional oil.

Other embodiments and modifications of the present invention may occurto those of ordinary skill in the art subsequent to a review of theinformation presented herein; these embodiments and modifications, aswell as equivalents thereof, are also included within the scope of thisinvention.

What is claimed is:
 1. A process which comprises (a) generating onelectrostatic latent image on an imaging member: (b) developing thelatent image by contacting the imaging member with a developer; (c)transferring the developed image to a copy substrate; and (d) affixingthe developed image to the copy substrate by contacting the developedimage with a fuser member comprising a substrate, a layer thereovercomprising a polymer, and, on the polymeric layer, a coating of arelease agent comprising the reaction product of (a) a primary- orsecondary-amino-functionalized polyorganosiloxane oil and (b) a compoundwhich is a low molecular weight, non-sterically-hindered aldehyde orketone.
 2. A process according to claim 1 wherein the polyorgonosiloxaneoil is of the formula

wherein R₁, R₂, R₃, R₄, R₅, R₆, R₇, R₈, and R₉ each, independently ofthe others, are alkyl or arylalkyl groups, wherein one or more of R₄, R₅and R₉ can also be a polyorganosiloxane chain with from 1 to about 100repeat diorganosiloxane monomer units, R₁₀ is an alkyl or arylalkylgroup, R₁₁ is a hydrogen atom, on alkyl or arylalkyl group, and p and nare each integers representing the number of repeat monomer units,wherein p must be at least 1 in at least some of the polyorganosiloxanemolecules.
 3. A process according to claim 1 wherein the aldehyde orketone is of the formula

wherein each of R₂₁ and R₂₂ independently of the other, is an alkylgroup, wherein one of R₂₁ and R₂₂ can also be a hydrogen atom.
 4. Aprocess according to claim 1 wherein the amino-functionalizedpolyorganosiloxane oil has an amine functionality of from about 0.01mole percent to about 10 mole percent.
 5. A process according to claim 1wherein the amino groups on the polyorganosiloxane oil are primary aminogroups.
 6. A process according to claim 1 wherein the compound is aketone.
 7. A process according to claim 1 wherein the reaction productis of the formula

wherein R₁, R₂, R₃, R₄, R₅, R₆, R₇, R₈, and R₉ each, independently ofthe others, are alkyl or arylalkyl groups, wherein one or more of R₄, R₅and R₉ can also be a polyorganosiloxane chain with from 1 to about 100repeat diorganosiloxane monomer units, R₁₀ is on alkyl or arylalkylgroup, each of R₂₁ and R₂₂, independently of the other, is an alkylgroup, wherein one of R₂₁ and R₂₂ can also be a hydrogen atom, and p andn are each integers representing the number of repeat monomer units,wherein p must be at least 1 in at least some of the polyorganosiloxanemolecules.
 8. A process according to claim 1 wherein the polymer is apolytetrafluoroethylene a fluorinated ethylene-propylene copolymer,polyfluoroalkoxypolytetrafluoroethylene, or a mixture thereof.
 9. Aprocess according to claim 1 wherein the polymer is a fluoroelastomer.10. A process according to claim 1 wherein the polymer is a copolymer ofvinylidenefluoride and hexafluoropropylene; a terpolymer ofvinylidenefluoride, hexafluoropropylene and tetrofluoroethylene; atetrapolymer of vinyildenefluoride, hexafluoropropylene,tetrafluoroethylene and a cure site monomer; or a mixture thereof.
 11. Aprocess according to claim 1 wherein the copy substrate is paper.
 12. Aprocess according to claim 1 wherein the amino-substitutedpolyorganosiloxane and the aldehyde or ketone are present in relativeamounts of at least about 25 moles of aldehyde or ketone per mole ofamino functional groups on the polyorganosiloxane.
 13. A processaccording to claim 1 wherein the amino-substituted polyorganosiloxaneand the aldehyde or ketone are present in relative amounts of at leastabout 100 moles of aldehyde or ketone per mole of amino functionalgroups on the polyorganosiloxane.
 14. A process according to claim 1wherein the reaction between the polyorganosiloxane oil and the aldehydeor ketone occurs at a temperature of at least about 300° F.